Fatally What?
by IWriteNaked
Summary: ONE SHOT. A spin off of Fatally Yours. The twins, Sebastian and Jonathan, get to know each other a little better, if you know what I mean... Rated M for SMUT, (or lemons, I guess) Incest, and language. This was requested, so I'm continuing Fatally Yours as if this never happened!


**This is kind of a spin off of Fatally Yours, as requested by someone.**

**If you haven't read Fatally Yours, you don't really have to. (Though, as the author, I think you should) All you really need to know to fully understand this one shot is that Valentine kidnaps a bunch of kids, and makes them get married/have sex... Jon and Sebastian are twins, but didn't meet until Jon was kidnapped a few weeks ago. Sebastian was raised by Valentine. Basically, Jon and Sebby are getting down in this one-shot. If you're not into it, don't read it.**

**WARNING****: Highly sexual content. SMUT. Incest. Language. RATED M FOR A REASON. Read at your own risk. AGAIN, if you're not into Jonbastian, don't read this. I don't want to hear about how I scarred you for life.**

**Disclaimer: I don't own the Mortal Instruments.**

-Jonathan Fray-

My '_wife,' _Aspen, is absolutely beautiful, and she moans perfectly when I fuck her the right way. She lets me do anything I want to her, and she never tells me no. There's no reason I shouldn't be incandescently happy with her, aside from the fact that we've all been kidnapped and forced to marry strangers. I like Aspen well enough.

I keep thinking of him though. When she talks about her family, when we kiss, when I slide into her. I wonder how different it would feel to be with Sebastian instead. My _twin brother. _"Damnit." I mutter, watching my guitar pick fall to the floor of the music room. It's the third time I've dropped it within the hour.

I've been unable to get through this song. My mind refuses to allow me to think of anything but _him. _Something about him is intriguing, in the sickest, most delicious kind of way. _I'm not even gay! _Never in my life has the idea of being with a man excited me, until I was taken here. Sebastian is the only man I've thought of in this way, and I don't understand why.

Part of me wants to murder him, for whatever it is that he did to make Clary so afraid of him. A bigger part of me wants to mold our bodies together.

I shake my head, trying to clear my thoughts as I lean forward to retrieve my fallen guitar pick. My thumb runs over the soft surface, gingerly. "Focus, Fray." I scold myself. I play through the song mechanically, finally managing to keep hold of the pick the entire time.

"You're very talented." Says a husky voice, coming from a far away place. I look up, my eyes trailing the length of his lean body, over sharp facial features to a black head of disheveled hair. "A little spaced out, but talented, nonetheless."

He tilts his head, black locks catching the light so entrancingly that my fingers actually twitch with desire to be ran through them. "What are you doing here, Sebastian?" I ask, focusing on keeping my voice steady.

He crosses the room swiftly, and takes the guitar from my lap. I lean my head to the side, eying him up and down while he's distracted with placing the acoustic back on it's stand. "I can leave, if you don't want me here." He says, the smirk audible in his voice, but not shown on his face. I gaze at his handsome features, trying to convince myself that the only reason I am attracted to my twin brother is because I am a cocky little shit.

"No, stay." I say, a little too quickly. My legs wobble as I stand, from being out of use for so long. I take deliberate steps toward him.

"No one has ever asked me to stay, Jonathan." He whispers my name, toward the ground. His voice is low and husky. My cock twitches. It's strange, a man's voice has never turned me on before. Sebastian Verlac is fucking my shit up.

"Don't say my name like that." I whisper into the empty space that separates us.

"Like what, Jonathan?" Sebastian gives me a stupid half smile. I would be lying if I said it didn't turn me on even more. His shirt says _Hell _in bold red lettering, and it hangs tightly from his torso. I have to restrain myself from ripping the thin fabric down the middle.

I swear that lust leaks from his eyes. "You're teasing me." I mutter inaudibly. He takes another step closer to me. One more step and I could close the distance.

Every muscle of his body is visible through his t-shirt. The curve of his chest, and the little gap where his pectoral muscles connect. A slight smirk plays on his lips when he notices me staring at him, and he winks, indicating that he may not be having very innocent thoughts either. This is all the permission I need. Suddenly, my body begins acting on impulse. Our chests press together, and I'm kissing him, my hands running through his raven black hair. It's silky and fine the way I imagined it would be. However, Sebastian doesn't return my kiss. "Kiss me back." I command.

He frowns, and I know he will reject me if I give him the opportunity. "What are you doing?" I tilt my head forward, looking at him through the curtain of white hair that's fallen over my face. His obsidian eyes hold something I've never seen in them before: Sadness. "You're always messing with my head." His hand fists into my t-shirt. "What are you doing?" He asks again, harshly.

My shoulders slump, and I break his gaze, but he doesn't release his hold on my t-shirt. I take this as a good sign, and back him against the wall, my arms forming a cage around him. "I want you." I admit, carefully. My heart drops into my stomach, waiting for his reply.

He cranes his neck, staring longingly at my lips. He bites his lip in the most distracting way, and my cock twitches again. "You do?" Sebastian sounds almost relieved. Excited, even.

My lips brush along his jawline, and he tilts his head to give me access to his neck. My tongue runs over his pulse, to his throat, tasting his skin. His neck vibrates against my lips when he groans. He pushes me away from his neck, leaning in to kiss me full on the mouth. I deepen the kiss, and my tongue slicks across his lips, pushing through, exploring his mouth. He tastes like lemonheads, and his tongue flicks expertly against mine. I'm still debating which one is turning me on more.

A groan leaves the back of my throat. My eyes become clouded with lust and dominance. Sebastian bites his lip, a grin of excitement spared over his flawless face. In one swift motion, he removes his shirt. I suppress a whimper at the sight of him. I knew he'd be beautiful, but his body looks better than I could have imagined. My hands run over the soft skin of his chest and abs, and I know that I will never want anyone else. Not this much, at least. "What do you want to do? I don't want to make you uncomfortable." I say, softly.

His eyes flick down to my chest, but they don't stop there. "I want to touch you." He says clearly. "I've wanted to touch you for so long." Sebastian fists the bottom of my t-shirt, dragging the hem up. I let him remove it, trying not to notice my heart pounding in my ears.

"How long?" I ask.

My twin brother stares at me for a second, as if he won't answer. Then he says "Since the first time I saw you. We were 14." He smiles at the memory, and I'm a little creeped out. They've been stalking us for that long. "It was the first time Father let me go with while he was watching you."

"What was I doing?"

"Clary was 12. You were sitting on a park bench, and she was drawing. You had your guitar. Father said you were teaching yourself to play." He starts unbuckling my belt. "I wanted to touch both of you. More than that though, I wanted to _be _you. I wanted to be normal, like you. I still do." By the time he's finished his explanation, my pants are on the floor.

He looks down at my body, seduction dripping from his gaze. I bite my lip, and pull him back into my chest. I slowly begin to play with his dark hair, letting my fingertips playfully stroke the side of his face, down his neck and over his collar bones. Sebastian inhales deeply, and I feel his hand creep under the waistband of my underwear.

I lean in, and slide my tongue over his pulse. The smirk on his face is replaced by a small gasp. His muscular arm snaked around my waist, pulling me closer to his chest. His hand presses into my back, like wet cement, while the other hand rubs up and down on my throbbing member.

Groans leave my parted lips, my hands leaving nail marks on his back. I love the feeling of his tensed muscles beneath my touch. My hand finds it's home around the growing bulge in Sebastian's pants, and my palm presses against him, flicking the button of his jeans open with one swift twist of my thumb. He flips us around, so my back is pressed into the wall. I bite down on his neck, marking him as mine.

I get distracted by the way his hard, lean body is curved against mine. His mouth trails down my chest, warm and insistent. Sebastian looks up at me from his knees. _Oh fuck, that's hot. _He smirks, dragging the last of my clothing down my legs. I fight back a whimper as he leans forward.

His tongue runs along my length, a relieved hum coming from me. I support myself against the wall, watching his every move. Sebastian takes the tip in his mouth, and bobs his head. "Fuck." My voice is barely a mumble, just loud enough for him to hear.

I take two handfuls of his hair, making him go deeper. I am in charge of him, and he enjoys every second of it. "You look so good like this." His chuckle is muffled, and it sends vibrations through me. "Fuck!" I exclaim again. His mouth was created for this, I swear it. I thrust into his mouth, and I think he appreciates it, small moans emanating from his mouth as I do it.

He desires to be used, so I use him. Hips thrusting, hands fisting into his raven hair, groaning his name. I pound into his mouth until he forcefully pushes against my hips to halt my movements. I throw my head back as he rocks his head back and forth, taking in as much as he can, then pulling back to swirl his tongue around the tip. "Sebastian," I growl. "I'm gonna - Oh my God." I cry out when he takes it all in, then pulls back, and I release on his chest. My tired body slumps lazily to the floor. "That was amazing."

He smiles, using his shirt to clean the come off of himself. "I'm glad you liked it." Sebastian presses his trembling lips on mine, and then pulls me closer to rest my head on his chest. Although I meant to stay with him for only a few minutes, the gently hum of him breathing, and Sebastian's heartbeat underneath me, lulled my exhausted body into a peaceful sleep.

**Not open to continuation. This is just a quick, hard fic against the wall.**

**Review! Okay, bye.**

**-IWriteNaked**


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